To know the contents of any subject you have to study it, often for long periods of time.
Nowadays, Fuzzy Maths has a two fold meaning.
One is more recent and refers to mathematics textbooks written in the spirit of constructivistic pedagogy. No drills, no rote - pure undertsanding of mathematical concepts through individual abstracting from suitable manipulatives.
The second meaning refers to the Fuzzy Mathematics that grew from the work of L. Zade from about 40 years ago. It'started with the Fuzzy Set Theory. Usual sets and elements have the property that any particular object either belongs or does not belong to a particular set. Zade called such relations crisp. In the Fuzzy Set Theory an element may belong to a set to a certain degree. For example, a 50 year old fellow is not yet an old man, but neither is he young any more. So if you consider the set of young people, the fellow can be said to belong to it with the degree of, say 0.3. A 20 year old belongs to the set with the degree of 1.
You should pick out the one meaning that interests you most and apply yourself to study it at depth.
All the best,